Alex replied:

G'day,
I'm not too sure of trips north of Perth other than the Pinnacles, but if you want to go east instead, there are some interesting things to see on the Hyden-Norseman road, such as Lake Cronin (if it has water, and if the roads open). Other options are to visit the Sandstone area of the goldfields, but you might want more than a night or two up there.
If you want more details, my email is alx110alex@netscape.net
Cheers,
Alex.

Jono replied:

Hi Jono,
Depends if you want to stay on the coast or go in land,,,, Ningham Station (check the spelling on that) on the great northern is only about 4.5 hours north of Perth and makes for a nice weekend away. Not too far and has some 4x4 runs but nothing too challanging. On the coast depending on how far you want to drive there is Jurien bay, North Hampton area and if your really keen Cape Perron or Steep point at Sharks Bay! I have done Steep point in a weekend but it was a very long trip for such a short stay!!!
There is also a great book you can get from most news agents for about $10 called weekend trips from Perth. This booklet has some good ideas and all the info on how to get there and points of interest.